The Drooling Disease. What Causes Excessive Saliva in Cats?


Cat viruses that cause drooling is an important topic for cat owners to understand, as these viruses can lead to potentially serious health issues. One of the most common viruses that causes excessive drooling in cats is Feline Calicivirus (FCV). This highly contagious virus is widespread in the cat population and can cause a range of symptoms beyond just drooling, including ulcers in the mouth, nasal discharge, and lethargy. While some cats recover fully, others can become chronic carriers of the virus. By learning about FCV and how it is transmitted, cat owners can take steps to diagnose, treat, and prevent infection in their pets. Understanding the causes, symptoms, and risks of viruses like FCV allows cat owners to proactively monitor their pet’s health and wellbeing.

What is Calicivirus?

Calicivirus, also known as feline calicivirus, is one of the most common upper respiratory viruses in cats. It is part of the Caliciviridae virus family and is highly contagious (1). Calicivirus infects the oral cavity and upper respiratory tract of cats, causing symptoms like ulcers in the mouth, sneezing, and nasal discharge. It is spread easily between cats through direct contact, shared food/water bowls, and respiratory secretions (2). The virus can survive in the environment for several weeks, contributing to how rapidly it spreads between cats in shelters, boarding facilities, and multi-cat households.




The main symptoms of calicivirus infection in cats include:

  • Fever – Calicivirus causes a high fever often over 104°F (40°C).
  • Sneezing – Nasal discharge and congestion cause sneezing.
  • Runny nose – Excess nasal discharge can be clear, yellow, or green.
  • Drooling – Ulcers in the mouth make eating painful and cause drooling.
  • Ulcers in the mouth – Painful ulcers develop on the tongue, gums, lips, and roof of the mouth.

According to the Cornell Feline Health Center, cats may drool excessively due to painful ulcers in the mouth caused by calicivirus. The mouth ulcers can become severe and cause oral pain, anorexia, and excessive drooling.


Feline calicivirus spreads through direct contact with infected cats. The main routes of transmission are exposure to saliva, nasal discharge, eye discharge, or aerosolized droplets from sneezing and coughing. Sharing food bowls, water bowls and grooming tools with an infected cat can also spread the virus. In addition, calicivirus can spread via fomites, which are inanimate objects that can carry infection, such as toys, bedding, food dishes, and human clothing and hands. The virus can survive in the environment for several weeks, allowing prolonged indirect transmission between cats. Prompt disinfection of shared items and housing areas is necessary to prevent spread. Isolating infected cats is also recommended to reduce transmission opportunities.


Diagnosing feline calicivirus infection typically involves veterinary tests to confirm the presence of the virus. Common diagnostic tests include:

PCR testing: This looks for the presence of viral DNA in samples from the mouth, nose or eyes. PCR can detect even small amounts of the virus.1

Virus isolation: Samples are taken from lesions and grown in cell cultures to try to isolate the live virus.2

Serology: Blood tests check for antibodies against calicivirus, which indicate exposure and an immune response to the virus.

It’s important to note that other feline diseases like herpesvirus and bacterial infections can cause similar symptoms to calicivirus. Diagnostic testing helps differentiate calicivirus from other potential causes.

Overall, veterinarians analyze the cat’s symptoms, medical history and diagnostic test results together to confirm a diagnosis of feline calicivirus.

1Source 1
2Source 2


There is currently no cure for feline calicivirus infection, so treatment focuses on supportive care to help the cat’s immune system fight the infection. Vets often recommend administering subcutaneous or intravenous fluids to prevent dehydration. Appetite stimulants may be prescribed if the cat is not eating due to oral pain. Soft foods and canned cat food can make eating more comfortable if the mouth ulcers are severe.

Antibiotics may be prescribed by the vet to treat or prevent secondary bacterial infections that can occur as a result of the ulcers and weakened immunity. Common antibiotics used include amoxicillin, clavamox, clindamycin, and doxycycline.

Some antiviral medications like ribavirin and human immunoglobulin have been used with limited success in experimental trials, but there are currently no antiviral drugs approved specifically for treating calicivirus in cats. Vaccination remains the best method of prevention.

While supportive care and symptom management are important, the virus itself cannot be cured at this time. The cat’s immune system must fight off the infection, which may take 1-2 weeks.


There are several steps cat owners can take to help prevent the spread of calicivirus:

Get your cat vaccinated. Vaccines can help prevent infection and reduce disease severity if a cat does get infected. Core vaccines like the feline herpesvirus/calicivirus vaccine are recommended for all cats by veterinarians.

Limit exposure to infected cats or contaminated objects. Keep cats with signs of illness separated from healthy cats. Disinfect any objects that may be contaminated before allowing contact.

Clean litter boxes daily. The calicivirus can survive in feces and be transmitted via contaminated litter.

Wash hands after handling cats. Human hands can spread the virus between cats.

Disinfect surfaces like food bowls, toys, beds with a diluted bleach solution. Bleach solutions properly kill the calicivirus.

Don’t allow cats to share food and water bowls. Saliva from an infected cat can contaminate shared dishes.


The prognosis for cats infected with calicivirus depends on the strain and severity. According to research from Cornell University, most cats recover completely after a calicivirus infection (source). However, virulent systemic strains can have a high mortality rate, with some reports of up to 67% (source).

In cats that survive an initial infection, calicivirus can produce a chronic carrier state. These carrier cats may continue to shed the virus and experience recurring symptoms throughout their lifetimes. Stress and other illnesses can trigger flare ups in previously infected cats (source). Therefore, while many cats fully recover, calicivirus has the potential to produce chronic illness in some patients.


Note that calicivirus is common but can be managed with proper care. New antiviral treatments are being researched. While there is no cure for feline calicivirus, most cats go on to live normal lives with supportive care from their veterinarian. With good nutrition, reducing stressors, keeping up with vaccines, and prompt treatment of symptoms, cats can remain happy and healthy despite contracting calicivirus. Research is ongoing for potential antiviral medications that may help treat or prevent calicivirus infections in cats.

Some key points from the sources:

– Calicivirus is very common in the cat population, with around 90% of cats having been exposed at some point (Feline Calicivirus, Cornell Vet)

– Most cats recover fully within 1-2 weeks with supportive care, though carrier state is possible (Calicivirus Infection in Cats, NIH)

– New antiviral treatments are being studied as a potential way to cure calicivirus infections in cats (Epidemiological Investigation of Feline Upper Respiratory Infections, NIH)


To summarize, calicivirus is a highly contagious cat virus that causes a variety of flu-like symptoms including conjunctivitis, ulcers in the mouth, limping or lameness, and excessive drooling. It spreads easily between cats through direct contact, contaminated surfaces, and airborne particles from sneezing. While some cats can experience more severe illness, many recover in 1-2 weeks with supportive care. Preventing exposure is key, so keeping cats up to date on vaccines, minimizing contact with infected cats, and maintaining clean environments are important. With prompt veterinary care and prevention efforts, the long-term outlook for cats with calicivirus can be positive.

Understanding this common feline virus is important for all cat owners and veterinarians. Being aware of the symptoms, transmission, diagnosis, and treatment will allow for earlier intervention and better management. Stopping the spread through careful isolation and disinfection is also critical. While calicivirus cannot be fully eliminated, its impact on cat health and wellbeing can be greatly minimized through diligent prevention and care.

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